1. Field of the Invention
The present invention relates to a method and a system for testing a vehicle underbody of a motor vehicle.
2. Description of the Related Art
A series of methods and devices are known for taking a picture of a vehicle underbody. In this context, a two-dimensional picture is taken as output. Other systems also exist, however, which supply three-dimensional information. In some methods, the three-dimensional sets of information are gathered from takes from different viewing angles. Other methods produce three-dimensional sets of information from a projection of laser lines on the vehicle underbody.
For this purpose, a mobile device is frequently used having wheels and a rod on which there is a mirror. This form of manual-optical inspection has the advantage that it may be used in mobile fashion. However, the middle section of the vehicle underbody is mostly not reached, using this item.
US Patent application publication 2002 009 732 1 A1 describes a device having a rod that has a digital camera on it.
Published international patent application document WO 2004 11 00 54 A1 describes a remote controlled platform which is equipped with one or more cameras.
US Patent application publication 2008 211 914 A1 describes a method for the automatic production of an underbody picture using a line scan camera. In the method described there, the travel direction and the speed of the vehicle are also recorded by additional sensors, in order to produce an overall picture having sufficient quality.
US Patent application publication 2007 027 376 0 A1 describes how an overall picture may be produced from the images of a plurality of area scan cameras. The position and the direction of view of the cameras relative to one another have to be known ahead of time. This relative orientation is ascertained by calculation, using the angular aperture of the cameras, the direction of view of the cameras with respect to the vertical and the expected distance between the cameras and the underbody. The individual images are rectified and combined to form a single underbody picture.
In Published European patent application document EP 1 619 625 A2 it is described that a plurality of cameras are used in a predefined linear or two-dimensional or three-dimensional arrangement, so that the field of view of each camera overlaps at least partially with the field of view of at least one other camera. The generated image data from this system may also be processed further so as to generate a three-dimensional picture.
One further method for determining vehicle views including the generation of three-dimensional profile data is described in US Patent application publication 2009 290 757 A1. In the method described there, the measurement takes place according to the principle of laser triangulation. For this purpose, one or more cameras are configured with one or more laser lines in such a way that the laser lines have a specified angle with respect to the camera, and the laser lines imaged on the object lie within the field of view of the cameras. Furthermore, the stereo triangulation, while using two or more cameras, is also named as an alternative configuration for generating three-dimensional profile data.
US Patent application publication 2009 290 757 A1 describes a test stand, at which vehicles are taken from different perspectives. In this context, laser lines are projected onto the surface to enable a three-dimensional reconstruction. The entire vehicle or only a part of the vehicle is optionally reconstructed, in order to compare it to a model or a data set of takes, and thus to detect irregularities on the vehicle.
Published German patent application document DE 197 05 047 A1 relates to a method and a device for measuring a profile depth of a motor vehicle tire. In this context, the profile of the motor vehicle tire is acted upon by laser light from a laser. The laser light generates a patch of light onto the profile surface of the motor vehicle tire. The light reflected by the tire profile is recorded by an image resolving sensor. In the process, the image resolving sensor observes the position and/or the form of the patch of light. The signals of the image resolving sensor are processed to produce output data according to the profile depth. During the measurement, the motor vehicle tire is rotated, so that the measurement may be performed at a plurality of locations on the tire profile.
Devices and methods are available for special applications, such as at control stations on border crossings, approaches to, or roads already at a market, for video-based takes of a vehicle underbody. Systems both exist which take the entire underbody using a single take, and those which produce one underbody picture from a plurality of temporally or spatially offset takes.